Enchantments show allow items to override enchantability check, allowing other mod items to use your enchantments. But your custom enchantment does not allow that, causing compatibility issues.
The proper enchantability logic flow is:
Enchantment check if they can accept the item (as exception to EnchantmentCategory check)
Item check if they can accept the enchantment (as exception to EnchantmentCategory check)
https://github.com/Majrusz/MajruszLibrary/blob/91912ba0325377004f421d47deec1fa0ad96e73d/common/src/main/java/com/majruszlibrary/item/CustomEnchantment.java#L41
Enchantments show allow items to override enchantability check, allowing other mod items to use your enchantments. But your custom enchantment does not allow that, causing compatibility issues.
The proper enchantability logic flow is: